Optical memory, optical diffraction element, and recording method

Abstract

An optical memory includes a support and nanoparticles, each of which changes between a crystal phase and an amorphous phase when irradiated with light. The nanoparticles are supported by the support and spaced apart from each other in one or both of an in-plane direction of a face of the support and a direction normal to the face of the support.

The invention claimed is: 
     
       1. A light diffraction element comprising:
 cells having respective thicknesses or respective refractive indexes set independently; and 
 an optical memory, directly or indirectly disposed on the cells, comprising:
 a support; and 
 nanoparticles, each of which changes between a crystal phase and an amorphous phase when irradiated with light, wherein 
 
 the nanoparticles are supported by the support and spaced apart from each other in one or both of an in-plane direction of a face of the support and a direction normal to the face of the support, and 
 one or more of the nanoparticles are disposed in each of sections of the optical memory, wherein each of the sections is a region obtained by projecting a bottom face of each of the cells on to the face of the support. 
 
     
     
       2. A recording method that uses an optical memory, the recording method comprising:
 causing signal light waves to enter the optical memory, wherein
 each of the signal light waves has a spatial intensity distribution that represents information, and 
 the signal light waves are generated at time intervals; and 
 
 recording, on the optical memory, each of the signal light waves which serve as light for writing, wherein 
 the optical memory comprises nanoparticles, each of which changes between a crystal phase and an amorphous phase when irradiated with light, and 
 the nanoparticles are supported by the support and spaced apart from each other in one or both of an in-plane direction of a face of the support and a direction normal to the face of the support. 
 
     
     
       3. The recording method according to  claim 2 , wherein, in the recording, the signal light waves are recorded in different regions of the optical memory.